// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/http/http_auth_challenge_tokenizer.h"

#include "base/strings/string_tokenizer.h"

namespace net {

HttpAuthChallengeTokenizer::HttpAuthChallengeTokenizer(
    std::string::const_iterator begin,
    std::string::const_iterator end)
    : begin_(begin)
    , end_(end)
    , scheme_begin_(begin)
    , scheme_end_(begin)
    , params_begin_(end)
    , params_end_(end)
{
    Init(begin, end);
}

HttpAuthChallengeTokenizer::~HttpAuthChallengeTokenizer()
{
}

HttpUtil::NameValuePairsIterator HttpAuthChallengeTokenizer::param_pairs()
    const
{
    return HttpUtil::NameValuePairsIterator(params_begin_, params_end_, ',');
}

std::string HttpAuthChallengeTokenizer::base64_param() const
{
    // Strip off any padding.
    // (See https://bugzilla.mozilla.org/show_bug.cgi?id=230351.)
    //
    // Our base64 decoder requires that the length be a multiple of 4.
    int encoded_length = params_end_ - params_begin_;
    while (encoded_length > 0 && encoded_length % 4 != 0 && params_begin_[encoded_length - 1] == '=') {
        --encoded_length;
    }
    return std::string(params_begin_, params_begin_ + encoded_length);
}

void HttpAuthChallengeTokenizer::Init(std::string::const_iterator begin,
    std::string::const_iterator end)
{
    // The first space-separated token is the auth-scheme.
    // NOTE: we are more permissive than RFC 2617 which says auth-scheme
    // is separated by 1*SP.
    base::StringTokenizer tok(begin, end, HTTP_LWS);
    if (!tok.GetNext()) {
        // Default param and scheme iterators provide empty strings
        return;
    }

    // Save the scheme's position.
    scheme_begin_ = tok.token_begin();
    scheme_end_ = tok.token_end();

    params_begin_ = scheme_end_;
    params_end_ = end;
    HttpUtil::TrimLWS(&params_begin_, &params_end_);
}

} // namespace net
